# How to secure access to MinIO server with TLS [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io) This guide explains how to configure MinIO Server with TLS certificates on Linux and Windows platforms. 1. [Install MinIO Server](#install-minio-server) 2. [Use an Existing Key and Certificate with MinIO](#use-an-existing-key-and-certificate-with-minio) 3. [Generate and use Self-signed Keys and Certificates with MinIO](#generate-use-self-signed-keys-certificates) 4. [Install Certificates from Third-party CAs](#install-certificates-from-third-party-cas) ## 1. Install MinIO Server Install MinIO Server using the instructions in the [MinIO Quickstart Guide](http://docs.min.io/docs/minio-quickstart-guide). ## 2. Use an Existing Key and Certificate with MinIO This section describes how to use a private key and public certificate that have been obtained from a certificate authority (CA). If these files have not been obtained, skip to [3. Generate Self-signed Certificates](#generate-use-self-signed-keys-certificates) or generate them with [Let's Encrypt](https://letsencrypt.org) using these instructions: [Generate Let's Encrypt certificate using Certbot for MinIO](https://docs.min.io/docs/generate-let-s-encypt-certificate-using-concert-for-minio.html). Copy the existing private key and public certificate to the `certs` directory. The default certs directory is: * **Linux:** `${HOME}/.minio/certs` * **Windows:** `%%USERPROFILE%%\.minio\certs` **Note:** * Location of custom certs directory can be specified using `--certs-dir` command line option. * Inside the `certs` directory, the private key must by named `private.key` and the public key must be named `public.crt`. * A certificate signed by a CA contains information about the issued identity (e.g. name, expiry, public key) and any intermediate certificates. The root CA is not included. ## 3. Generate and use Self-signed Keys and Certificates with MinIO This section describes how to generate a self-signed certificate using various tools: * 3.1 [Use generate_cert.go to Generate a Certificate](#using-go) * 3.2 [Use OpenSSL to Generate a Certificate](#using-open-ssl) * 3.3 [Use OpenSSL (with IP address) to Generate a Certificate](#using-open-ssl-with-ip) * 3.4 [Use GnuTLS (for Windows) to Generate a Certificate](#using-gnu-tls) **Note:** * MinIO only supports keys and certificates in PEM format on Linux and Windows. * MinIO doesn't currently support PFX certificates. ### 3.1 Use generate_cert.go to Generate a Certificate Download [`generate_cert.go`](https://golang.org/src/crypto/tls/generate_cert.go?m=text). `generate_cert.go` is a simple *Go* tool to generate self-signed certificates, and provides SAN certificates with DNS and IP entries: ```sh go run generate_cert.go -ca --host "10.10.0.3" ``` A response similar to this one should be displayed: ``` 2018/11/21 10:16:18 wrote cert.pem 2018/11/21 10:16:18 wrote key.pem ``` Rename `cert.pem` to `public.crt` and `key.pem` to `private.key`. ### 3.2 Use OpenSSL to Generate a Certificate Use one of the following methods to generate a certificate using `openssl`: * 3.2.1 [Generate a private key with ECDSA](#generate-private-key-with-ecdsa) * 3.2.2 [Generate a private key with RSA](#generate-private-key-with-rsa) * 3.2.3 [Generate a self-signed certificate](#generate-a-self-signed-certificate) #### 3.2.1 Generate a private key with ECDSA. Use the following command to generate a private key with ECDSA: ```sh openssl ecparam -genkey -name prime256v1 | openssl ec -out private.key ``` A response similar to this one should be displayed: ``` read EC key writing EC key ``` Alternatively, use the following command to generate a private ECDSA key protected by a password: ```sh openssl ecparam -genkey -name prime256v1 | openssl ec -aes256 -out private.key -passout pass:PASSWORD ``` **Note:** NIST curves P-384 and P-521 are not currently supported. #### 3.2.2 Generate a private key with RSA. Use the following command to generate a private key with RSA: ```sh openssl genrsa -out private.key 2048 ``` A response similar to this one should be displayed: ``` Generating RSA private key, 2048 bit long modulus ............................................+++ ...........+++ e is 65537 (0x10001) ``` Alternatively, use the following command to generate a private RSA key protected by a password: ```sh openssl genrsa -aes256 -out private.key 2048 -passout pass:PASSWORD ``` **Note:** When using a password-protected private key, the password must be provided through the environment variable `MINIO_CERT_PASSWD` using the following command: ```sh export MINIO_CERT_PASSWD= ``` The default OpenSSL format for private encrypted keys is PKCS-8, but MinIO only supports PKCS-1. An RSA key that has been formatted with PKCS-8 can be converted to PKCS-1 using the following command: ```sh openssl rsa -in private-pkcs8-key.key -aes256 -passout pass:PASSWORD -out private.key ``` #### 3.2.3 Generate a self-signed certificate. Use the following command to generate a self-signed certificate and enter a passphrase when prompted: ```sh openssl req -new -x509 -days 3650 -key private.key -out public.crt -subj "/C=US/ST=state/L=location/O=organization/CN=" ``` **Note:** Replace `` with the development domain name. Alternatively, use the command below to generate a self-signed wildcard certificate that is valid for all subdomains under ``. Wildcard certificates are useful for deploying distributed MinIO instances, where each instance runs on a subdomain under a single parent domain. ```sh openssl req -new -x509 -days 3650 -key private.key -out public.crt -subj "/C=US/ST=state/L=location/O=organization/CN=<*.domain.com>" ``` ### 3.3 Use OpenSSL (with IP address) to Generate a Certificate This section describes how to specify an IP address to `openssl` when generating a certificate. #### 3.3.1 Create a configuration file. Create a file named `openssl.conf` with the content below. Change `IP.1` to point to the correct IP address: ```sh [req] distinguished_name = req_distinguished_name x509_extensions = v3_req prompt = no [req_distinguished_name] C = US ST = VA L = Somewhere O = MyOrg OU = MyOU CN = MyServerName [v3_req] subjectAltName = @alt_names [alt_names] IP.1 = 127.0.0.1 ``` #### 3.3.2 Run `openssl` and specify the configuration file: ```sh openssl req -x509 -nodes -days 730 -newkey rsa:2048 -keyout private.key -out public.crt -config openssl.conf ``` ### 3.4 Use GnuTLS (for Windows) to Generate a Certificate This section describes how to use GnuTLS on Windows to generate a certificate. #### 3.4.1 Install and configure GnuTLS. Download and decompress the Windows version of GnuTLS from [here](http://www.gnutls.org/download.html). Use PowerShell to add the path of the extracted GnuTLS binary to the system path: ``` setx path "%path%;C:\Users\MyUser\Downloads\gnutls-3.4.9-w64\bin" ``` **Note:** PowerShell may need to be restarted for this change to take effect. #### 3.4.2 Generate a private key: Run the following command to generate a private `.key` file: ``` certtool.exe --generate-privkey --outfile private.key ``` A response similar to this one should be displayed: ``` Generating a 3072 bit RSA private key... ``` #### 3.4.3 Generate a public certificate: Create a file called `cert.cnf` with the content below. This file contains all of the information necessary to generate a certificate using `certtool.exe`: ``` # X.509 Certificate options # # DN options # The organization of the subject. organization = "Example Inc." # The organizational unit of the subject. #unit = "sleeping dept." # The state of the certificate owner. state = "Example" # The country of the subject. Two letter code. country = "EX" # The common name of the certificate owner. cn = "Sally Certowner" # In how many days, counting from today, this certificate will expire. expiration_days = 365 # X.509 v3 extensions # DNS name(s) of the server dns_name = "localhost" # (Optional) Server IP address ip_address = "127.0.0.1" # Whether this certificate will be used for a TLS server tls_www_server ``` Run `certtool.exe` and specify the configuration file to generate a certificate: ``` certtool.exe --generate-self-signed --load-privkey private.key --template cert.cnf --outfile public.crt ``` ## 4. Install Certificates from Third-party CAs MinIO can connect to other servers, including MinIO nodes or other server types such as NATs and Redis. If these servers use certificates that were not registered with a known CA, add trust for these certificates to MinIO Server by placing these certificates under one of the following MinIO configuration paths: * **Linux:** `~/.minio/certs/CAs/` * **Windows**: `C:\Users\\.minio\certs\CAs` # Explore Further * [TLS Configuration for MinIO server on Kubernetes](https://github.com/minio/minio/tree/master/docs/tls/kubernetes) * [MinIO Client Complete Guide](https://docs.min.io/docs/minio-client-complete-guide) * [Generate Let's Encrypt Certificate](https://docs.min.io/docs/generate-let-s-encypt-certificate-using-concert-for-minio) * [Setup nginx Proxy with MinIO Server](https://docs.min.io/docs/setup-nginx-proxy-with-minio)